Dunno if you have tried this, but the Seabright humane mouse trap is the best i've ever used. I've caught several mice in an hour with this trap and even two mice at once (lol). I ended up filing down the latch/trigger mechanism a tiny bit so that it became even more sensitive.
Good luck!
http://www.seabrightlabs.com/mouse.htm
RE: The Mice Are Ninjas